This protocol is proposed for the preparation of dispersions for generic acute eco-toxicity applications; its use for chronic toxicity or other environmental studies, while potentially efficacious, is beyond the scope of the present work and should be validated by use of proper controls. In this protocol, a TiO2 nanoparticle dispersion in a relevant environmental matrix is produced by following a series of steps applied to a TiO2 aqueous nanoparticle stock. Following the Organization for Economic Cooperation and Development (OECD) Guideline 202 for testing of chemicals, the environmental matrix used in this work is reconstituted from four stock solutions defined in ISO 6341, yielding a calculated hardness of ≈ 170 mg/kg (ppm) as CaCO3. In this protocol, humid acid (HA) is utilized as a stabilizing agent to disperse SRM 1898 in the selected test matrix. Natural organic matter – and humid acid in particular – has been demonstrated to function as a non-specific stabilizer in environmental matrices.
2.Principles and scope
4.Reagents, materials and equipment
5.Preparation of TiO2 nanoparticle dispersions